(1) Field of the Invention
This invention relates to sampling fluids and particularly for a 99+% volumetric efficient pump for sampling fluids and especially gases as well as liquids from pipe lines. Persons concerned with the quality of fluids being transmitted in pipe lines have ordinary skill in this art.
(2) Description of the Related Art
The inventor previously received U.S. Pat. No. 4,531,895 on the Jul. 30, 1985 for a Gas Sampling Pump. That patent disclosed a pump having a very high volumetric efficiency in taking samples from a pipe line. That pump included an exterior line to the pump so there would be a balanced valve within the pump. Also, that pump had at least three O-rings sealing the riciprocating plunger from the bore within which it worked.
Use of this pump has indicated certain limitations of its utility because of the friction between the O-rings and the plunger. Also, the exterior line identified by the numeral 84 in the patent as the balance conduit, made it clumsy or difficult to install and remove for service.